Three-Day Diet and Grapefruit

Jill Corleone

About the Author:

Jill Corleone

Jill Corleone is a registered dietitian and health coach who has been writing and lecturing on diet and health for more than 15 years. Her work has been featured on the Huffington Post, Diabetes Self-Management and in the book "Noninvasive Mechanical Ventilation," edited by John R. Bach, M.D. Corleone holds a Bachelor of Science in nutrition.

If you have a special event or a beach vacation coming up, losing 10 pounds in a week on the three-day diet with grapefruit sounds like the way to go. But this very low-calorie diet, also referred to as the Military diet, may help you lose more water and muscle than fat. Any diet that makes big weight-loss claims is considered a fad diet, and not usually the healthiest way to lose weight and keep it off. Consult your doctor about a healthy diet for you.

A closeup of a grapefruit.
(Image: Medioimages/Photodisc/Photodisc/Getty Images)

The Diet Plan

According to the Military Diet website, the food choices on the diet increase your metabolism and help you burn fat and lose weight. Each day during the three-day diet period, you consume three very specific meals with unlimited amounts of water and black coffee. For example, breakfast on day one includes coffee, one slice of toast with 2 tablespoons of peanut butter and half of a grapefruit, and lunch is 1/2 cup of tuna, one slice of toast and plain coffee or tea. Grapefruit is only eaten at breakfast on day one of the diet plan. You follow the diet for three days and then take four days off, and continue this pattern until you've reached your goal.

Diet Weight-Loss Claims

The three-day diet with grapefruit claims that there are a few factors of the diet that help you lose weight. First, it's a low-calorie diet that helps you eat fewer calories than you burn, creating a negative calorie balance to help you lose unwanted weight. Also, it is considered an intermittent fasting diet, which may help improve insulin levels, aiding in weight management, according to the Military Diet website. The specific foods on the diet plan also supposedly aid in weight loss. The caffeine in all the coffee you're allowed to drink helps boost your metabolism, while the grapefruit helps you burn fat.

Unraveling the Claims

During the three days, you are eating fewer than 1,000 calories each day, according to the Military Diet website. On a very low-calorie diet, you will lose weight if you follow the plan. Intermittent fasting may help promote weight loss in the short term, but it has not been successful at helping people keep the weight off, according to a 2014 review article published in "Maturitas." Some evidence indicates that caffeine may boost your metabolism, but the research is limited and flimsy, says NHS Choices. Dietitian Juliette Kellow at Weightlossresources.co.uk reports new research shows that grapefruit may help improve insulin levels and weight loss, but more studies are necessary before claims can be made.

Concerns About Diet

As with many other fad diets, you may be able to lose weight following the three-day diet with grapefruit, but you may have a hard time keeping it off. Dieters often become bored following strict diet plans, according to the University of Pittsburgh Medical Center, making them difficult to follow over the long term. If you want to lose weight and stop dieting, find a plan that helps you reasonably and safely limit calories and control portions, and includes a variety of nutrient rich foods from all the food groups. Your plan should help you lose weight at a healthy rate of 1 to 2 pounds a week.